John Guretzky  Associate Professor and Grassland Systems Ecologist

John Guretzky portrait

Contact Information

Area of Focus

Grassland Systems Ecology

Mob Grazing Research

UNL Mob Grazing Research


  • B.S., Natural Resources (Environmental Studies), University of Nebraska-Lincoln, 1996
  • Ph.D., Crop Production and Physiology, Iowa State University, 2002

Research Interests

  • Structure and function of grassland systems
  • Forage-beef production systems
  • Use of perennial grasses in biomass energy systems

Teaching Interests

  • Forage crop and range management
  • Perennial plant function, growth, and development
  • Grassland research techniques and analysis

Extension Interests

  • Providing Nebraskans with the best information available about forage and grasslands to meet their production and land management goals

Selected Publications

  • Biermacher, J.T., R. Reuter, J. Guretzky, M. Kering, J. Rogers, J. Blanton, Jr., and T. Butler. 2012. Expected economic potential of substituting legumes for nitrogen in bermudagrass pastures. Crop Science. Accepted / In Press.
  • Guretzky, J.A., T.J. Butler, and J. Muir. 2012. Adaptation of annual forage legumes in the southern Great Plains. Great Plains Research. Accepted / In Press.
  • Kering, M.K., J.T. Biermacher, T.J. Butler, J. Mosali, and J.A. Guretzky. 2012. Biomass yield and nutrient responses of switchgrass to phosphorus fertilization. Bioenergy Research. 5:71-78.
  • Kering, M.K., T.J. Butler, J.T. Biermacher, and J.A. Guretzky. 2012. Biomass yield response of five perennial grasses to four nitrogen rates. Bioenergy Research. 5:61-70.
  • Kering, M.K., J. Guretzky, J. Mosali, and E. Funderburg. 2011. Effect of nitrogen fertilizer rate and harvest season on forage yield, quality, and macronutrient concentrations in -Midland' bermudagrass. Communications in Soil Science and Plant Analysis 42:1958-1971.
  • Guretzky, J.A., J.T. Biermacher, B.J. Cook, M.K. Kering, and J. Mosali. 2011. Switchgrass for forage and bioenergy: harvest and nitrogen rate effects on biomass yields and nutrient composition. Plant Soil. 339:69-81.
  • Guretzky, J.A., M. Kering, J.T. Biermacher, E. Funderburg, and J. Mosali. 2010. Fertilizer rate effects on forage yield stability and nutrient uptake of Midland bermudagrass. Journal of Plant Nutrition. 33:1819-1834.
  • Guretzky, J.A., M.K. Kering, J.T. Biermacher, and B.J. Cook. 2009. Switchgrass for forage and bioenergy: II. Effects of P and K fertilization. The Proceedings of the International Plant Nutrition Colloquium XVI. University of California, Davis. Online.
  • Kering, M.K., J.T. Biermacher, B.J. Cook, and J.A. Guretzky. 2009. Switchgrass for forage and bioenergy: I. Effects of nitrogen rate and harvest system. The Proceedings of the International Plant Nutrition Colloquium XVI. University of California, Davis. Online.
  • Guretzky, J.A., Ball, J., and Cook, B.J. 2008. Nitrogen fertilizer rate and weather dictate nutritive value of fall stockpiled bermudagrass. Online. Forage and Grazinglands doi:10.1094/FG-2008-0118-01-RS.
  • Guretzky, J.A., K.J. Moore, C.L. Burras, and E.C. Brummer. 2007. Plant species richness in relation to pasture position, management, and scale. Agriculture, Ecosystems & Environment. 122:387-391.
  • Guretzky, J.A., J.S. Fehmi, and A.B. Anderson. 2006. Grazing and military vehicle interaction on grassland soils and vegetation. Great Plains Research. 16:51-61.
  • Guretzky, J.A., K.J. Moore, E.C. Brummer, and C.L. Burras. 2005. Species diversity and functional composition of pastures that vary in landscape position and grazing management. Crop Science. 45:282-289.
  • Guretzky, J.A., K.J. Moore, C.L. Burras, and E.C. Brummer. 2004. Distribution of legumes along gradients of slope and soil electrical conductivity (ECa) in pastures. Agronomy Journal. 96:547-555.
  • Guretzky, J.A., K.J. Moore, A.D. Knapp, and E.C. Brummer. 2004. Emergence and survival of legumes seeded into pastures varying in landscape position. Crop Science. 44:227-233.
  • Guretzky, J.A. and S.M. Louda. 1997. Evidence for natural biological control: insects decrease survival and growth of a native thistle. Ecological Applications. 7:1330-1430.